package 多线程.单例模式;

public class Singleton {
    private volatile static Singleton singleton = null;
    private Singleton(){
        
    }
    public static Singleton getInstance(){
        if(singleton==null){
            synchronized(Singleton.class){
                if(singleton==null){
                    singleton = new Singleton();
                }
            }
        }
        return singleton;
    }
}
